When two eyes view a three dimensional world, the images in each eye will frequently be mismatched. The visual system can eliminate the confusion that would result from a large mismatch by suppressing the perception of input to one eye. Thus, if a vertical grating is presented to one eye and a horizontal to the other, vertical and horizontal contours may be seen, but a plaid, combining both gratings is never seen. The perception of a temporally unstable pattern of vertical and horizontal regions is known as binocular rivalry. If, however, the orthogonal gratings are presented stroboscopically (e.g. 6 msec flashes at 6 Hz), rivalry fails to develop and the gratings do appear to fuse into a plaid pattern. Investigations of this unusual binocular phenomenon, "false fusion", suggest that it may help us to a better understanding of binocular vision and some of its pathologies because it allows us to manipulate the mechanism controlling binocular vision in a way not previously possible. The first part of our research will use false fusion to explore the binocular pathways of normal observers. We will study the influence of spatial and temporal factors on false fusion. Further, we will study the influence of false fusion on other binocular effects such as stereopsis. In the second half of the proposed research, we will study binocularly abnormal individuals. In some people suppression is pathological, rendering them monocular during binocular viewing. In these individuals, many of whom never experience "true" fusion, we will attempt to produce false fusion. If this is possible, we will have provided a form of binocular experience to people normally deprived of it. Such a technique might be used to alleviate some of the effects of their binocular pathologies.